Atten ST862D hot air station weird message!!

[petemanuk]

Went to use my Atten ST862D hot air station today all fired up as normal but after few min's the heat stopped (air stil blowing) and the display popped up with the messasge COL.

I've read the manual (all 6 pages of it) from cover to cover but no mention of a display message COL ??

I'm guessing the heating element has gone and will investigate futher but just wondered if enyone else with an Atten ST862D has seen this message an knew what it ment? Just incase its something else.